diff options
| author | Janosch Frank <frankja@linux.ibm.com> | 2018-08-01 11:48:28 +0100 |
|---|---|---|
| committer | Janosch Frank <frankja@linux.ibm.com> | 2018-09-12 14:46:37 +0200 |
| commit | 40ebdb8e59df36e2cc71810bd021a0808b16c956 (patch) | |
| tree | 636895d9c4298e3c178ee73fc7ff00e1e5345aa0 /arch/s390 | |
| parent | 1843abd03250115af6cec0892683e70cf2297c25 (diff) | |
KVM: s390: Make huge pages unavailable in ucontrol VMs
We currently do not notify all gmaps when using gmap_pmdp_xchg(), due
to locking constraints. This makes ucontrol VMs, which is the only VM
type that creates multiple gmaps, incompatible with huge pages. Also
we would need to hold the guest_table_lock of all gmaps that have this
vmaddr maped to synchronize access to the pmd.
ucontrol VMs are rather exotic and creating a new locking concept is
no easy task. Hence we return EINVAL when trying to active
KVM_CAP_S390_HPAGE_1M and report it as being not available when
checking for it.
Fixes: a4499382 ("KVM: s390: Add huge page enablement control")
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20180801112508.138159-1-frankja@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f69333fd2fa3..ac5da6b0b862 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -481,7 +481,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; case KVM_CAP_S390_HPAGE_1M: r = 0; - if (hpage) + if (hpage && !kvm_is_ucontrol(kvm)) r = 1; break; case KVM_CAP_S390_MEM_OP: @@ -691,7 +691,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) mutex_lock(&kvm->lock); if (kvm->created_vcpus) r = -EBUSY; - else if (!hpage || kvm->arch.use_cmma) + else if (!hpage || kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) r = -EINVAL; else { r = 0; |